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[Licence| Download | New Version Template] aanz_v2_0.tar.gz(4 Kbytes)
Manuscript Title: NumSBT: A subroutine for calculating spherical Bessel transforms numerically.
Authors: J.D. Talman
Program title: NumSBT
Catalogue identifier: AANZ_v2_0
Distribution format: tar.gz
Journal reference: Comput. Phys. Commun. 180(2009)332
Programming language: Fortran 90.
Computer: Generic.
Operating system: Linux.
Keywords: Fourier transforms, Spherical Bessel functions, Hankel transforms.
PACS: 02.60.Jh.
Classification: 4.6.

Does the new version supersede the previous version?: No

Nature of problem:
This program is a subroutine which, for a function defined numerically on a logarithmic mesh in the radial coordinate, generates the spherical Bessel, or Hankel, transform on a logarithmic mesh in the transform variable. Accurate results for large values of the transform variable are obtained, that would not be otherwise obtainable.

Solution method:
The program applies a procedure proposed by the author [1] that treats the problem as a convolution. The calculation then requires two applications of the fast Fourier transform method.

Reasons for new version:
The method of computing the transform at small values of the transform variable has been substantially changed and the whole procedure simplified. In addition, the possibility of computing the transform for a single transform variable value has been incorporated. The code has also been converted to Fortran 90 from Fortran 77.

The procedure is most applicable to smooth functions defined on (0, ∞) with a limited number of nodes.

Running time:
The example provided with the distribution takes a few seconds to execute.

[1] J.D. Talman, J. Comp. Phys. 29 (1978) 35